An anatomy scan is a routine prenatal ultrasound conducted during the middle stage of pregnancy, typically between 18 and 22 weeks. Its primary purpose is to assess the developing fetus, ensuring expected growth and identifying any potential developmental variations or conditions.
Typical Scan Duration
A standard anatomy scan usually takes approximately 30 to 75 minutes. While some scans might be quicker, around 20-30 minutes, others can extend to an hour or longer. The duration varies based on several factors.
What the Scan Examines
During the anatomy scan, the sonographer systematically examines various aspects of the baby’s body and surrounding environment, including:
- The fetal brain, including its fluid-filled spaces and cerebellum, and skull formation.
- The baby’s heart, ensuring four chambers and expected blood flow through major arteries.
- The spine, along its entire length, to confirm integrity.
- Facial features, such as the lips and nose.
- The chest, to examine the lungs and diaphragm.
- Abdominal organs, including the stomach, kidneys, bladder, and intestines, for typical development and position.
- Measurements of the baby’s head circumference, abdominal circumference, and femur length to estimate growth and weight.
- The umbilical cord, verifying the appropriate number of vessels and its attachment to the placenta.
- The position of the placenta and the volume of amniotic fluid surrounding the baby.
Factors Affecting Scan Time
Several elements can influence how long an anatomy scan takes. The baby’s position within the uterus is a significant factor; if the baby is not in an ideal orientation, the sonographer may need more time, or the parent might be asked to move around to encourage a better view. For instance, if the baby’s spine is facing the front, it can obscure views of the heart or face, requiring adjustments.
The clarity of the ultrasound images also impacts duration. Factors such as maternal body mass index (BMI) or the presence of scar tissue can affect image quality, requiring the sonographer to spend additional time to ensure all necessary details are captured.
Sometimes, the baby’s activity level can prolong the scan. An overly active baby might make it difficult to get precise measurements, while a very still baby might be in a position that hides certain anatomy.
In some instances, if an area needs a closer look or if the baby does not cooperate, a follow-up appointment might be necessary to complete the examination. The sonographer’s experience also plays a role, as more experienced professionals may be able to complete the scan more efficiently.